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A visible light driven 1D/2D-NiMoO4/BiOI nanocomposite photocatalyst was constructed by single step solvothermal method. Here, various composition of NiMoO4/BiOI nanocomposites were prepared by loading different amounts of NiMoO4 (1, 2, 3 wt %) to the BiOI. Among the as-prepared photocatalysts, 1 wt % of NiMoO4 on BiOI (NMBI-1) showed superior photocatalytic activity (92.7 %) under visible light irradiation. On analysis, the optimized NMBI-1 exhibited a lower bandgap energy value of 1.64 eV and also found to show around 2 and 3.7-times higher degradation ability for the removal of MB than the pure NiMoO4 and BiOI respectively. In addition, the optimized NMBI-1 nanocomposite photocatalyst exhibited excellent photostability and recyclability properties. The charge carriers on the interface of the NiMoO4 and BiOI enabled the easy transfer via the newly formed heterojunction, thereby increasing the photocatalytic performance. Additionally, the radical scavengers such as h+ and .OH were found to be the major species in the removal of MB under visible light illumination. Therefore, the 1D/2D-NiMoO4/BiOI nanocomposite photocatalyst materials could possibly be considered for the wastewater remediation processes.

In this research literature, a tungsten disulfide/iron cobaltite (WS

Amine-functionalized ZnO nanorods@graphene oxide (ZnO-NR/NH2/GO) nanocomposites prepared by a facile solution route have been investigated through X-ray diffraction, diffuse reflectance spectra, Raman spectra, scanning electron microscopy and transmission electron microscopy. The amine-functionalized ZnO-NR/NH2/GO-2 nanocomposite exhibits very strong visible light absorption. Dye-sensitized solar cell (DSSC) made of ZnO-NR/NH2/GO-2 nanocomposite (with optimum 2 wt % GO) photoanode delivers a power conversion efficiency (PCE) of 3.76% which is much higher than the efficiency of unmodified ZnO-NR/GO photoanodes based DSSC (2.27%). The enhancement of PCE is primarily caused by the increased current density, attributed to the incorporation of aminosilicate and GO on the surface of ZnO-NRs which facilitates rapid transfer of electron from conduction band of ZnO to conducting surface of FTO. This diminished recombination of photogenerated electrons and holes improve the electron transfer at the photoanode/electrolyte interfaces.

In this study, 250 nm sized porous anatase TiO2 nanospheres (TiO2 NSPs) composed of ∼ 10 nm sized anatase TiO2 nanoparticles are obtained through a green synthetic route and their surfaces have been decorated with 3–4 nm sized plasmonic silver nanoparticles (AgNPs). Photoluminescence studies confirm that the AgNPs presence on TiO2 NSPs surface effectively inhibits the radiative charge recombination and thus facilitates charge separation process at the Ag-TiO2 NSPs interface, causing an enhanced photocatalytic activity. About 92% of the ceftiofur sodium (CFS) antibiotic taken initially is oxidized by Ag-TiO2 NSPs upon 90 min white light irradiation, while Ag loaded Degussa P25 TiO2 nanoparticles effects only 71% CFS oxidation. The synergistic effect given by plasmonic AgNPs and the continuous framework of anatase TiO2 NPs contributes to inhibit the electron-hole recombination in the Ag-TiO2 NSPs. Oxidation products of CFS in different water sources and their eco-toxicity effects identified through LC-MS and microtox-bioassays, respectively, indicate that the obtained oxidation products are non-toxic compared to pure CFS. Therefore, porous Ag-TiO2 NSPs could be successfully applied in photocatalytic oxidation technologies, exploiting sunlight for the effective removal of pharmaceutical pollutants from wastewater.

Supercapacitors are progressively being utilized for storage systems in sustainable nanotechnologies. A NiCoS nanostructure was synthesized on nickel foam by an in situ one-pot hydrothermal method at different reaction temperatures (80, 100, and 120 °C) keeping other reaction parameters such as pH and reaction time constant for supercapacitor applications. The SEM report revealed a plate-like nanostructures of NiCoS on nickel foam (NiCoS/NF). The electrode prepared at 100 °C exhibits better electrochemical activities compared to electrodes prepared at 80 and 120 °C. The integrated binder-free NiCoS/NF electrode for supercapacitor, optimized at 100 °C, manifested a large specific capacitance of 3309 mF cm−2 at a current density of 1 mA cm−2 with a notable rate capability of 427 mF cm−2 even at 10 mA cm−2. The asymmetric supercapacitor fabricated with optimized NiCoS/NF prepared at 100 °C exhibited an exceptionally high energy density of 2.04 mW h cm−3 at a power density of 42.64 mW cm−3.

A series of ternary ZnO hollow sphere/carbon quantum dots/reduced graphene oxide (ZnO/CQDs/r-GO) nanocomposites were successfully prepared via solvothermal technique in the presence of the polyethylene glycol 400 (PEG 400) as a solvent. The structural details of as-prepared ZnO/CQDs/r-GO nanocomposites were characterized by powder X-ray diffraction analysis. The morphological properties of the composite were analyzed using field emission scanning microscopy (FE-SEM). The visible light absorption ability of the as-prepared pristine and ternary nanocomposites was examined using UV–visible (UV–Vis) spectrophotometry. The photocatalytic activity of ZnO, ZnO/CQDs, ZnO/r-GO, and ZnO/CQDs/r-GO nanostructures were evaluated for the degradation of organic pollutants such as methylene orange (MO), rhodamine B (RhB), and methylene blue (MB). The different composites with various amounts of reduced graphene oxide (r-GO) and carbon quantum dots (CQDs) were synthesized to enhance photocatalytic activity. The ZnO/CQDs/r-GO composites showed excellent potential for photocurrent generation compared with ZnO, ZnO/CQDs and ZnO/r-GO under-stimulated sunlight. The effect of various parameters such as the effect of reaction temperature, catalyst concentration, pH, and concentration of MB dye has been also studied. The photo-assisted catalytic degradation properties of the catalyst after five cycles exhibit high stability.

ZSM-5:CeO2 nanocomposites were prepared by two-step hydrothermal method in combination with the wet impregnation method. The synthesized nanocomposites were characterized by XRD, FESEM, TEM, EDX, elemental mapping, FTIR and UV–vis analysis. The bandgap investigations were done using tauc plot and the bandgap of ZSM-5 has been reduced from 3.90 to 3.15 eV upon CeO2 loading. The synthesized nanocomposites were tested for photocatalytic activity under a halogen lamp and the effect of CeO2 loading on ZSM5 has been examined. Among the various nanocomposites synthesized, ZSM-5:CeO2 25 wt% exhibited better methyl orange degradation of about 95.6% with an initial dye concentration of 10 mg/l, pH 7, 100 mg of photocatalyst under halogen lamp for 75 min. Additionally, the effect of various reaction parameters like dye concentration (10–25 mg/l), photocatalyst dosage (25–125 mg), and pH (3–9) was probed to get better performance. Tapping experiments were conducted with various radical scavengers to get insight into the key active species responsible for the photodegradation of methyl orange. The result portrays the importance of hydroxyl radical for the degradation of methyl orange dye. Cycle test and stability studies showed that the photocatalyst was stable even after four cycles. In summary, ZSM-5:CeO2 nanocomposites can be a suitable photocatalyst for numerous applications in the field of photodegradation of organic contaminants.

Bismuth sulfide (Bi2S3) nanorods have been prepared using a simple and low-cost reflux method. This method is easy to handle and opens up a way to manufacture photocatalytic pigment at a low cost. The Bi2S3 catalyst was subjected to X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis), scanning electron microscope, high-resolution transmission electron microscopy, FT-IR spectroscopy, thermogravimetric analysis (TG/DTA), and X-ray photoelectron spectroscopy. The structures of the Bi2S3 nanorod have been investigated and were seen to be orthorhombic. The electron microscopic observations showed that surfactants greatly affect the morphologies of the as-prepared Bi2S3 samples. The XRD and TEM results confirmed that the Bi2S3 nanorods have a high surface area and are good crystallinity. TEM measurements revealed that the average breadth and length is 75 nm and 385 nm for Bi2S3 nanorods prepared using NaOH. The uniform one-dimensional Bi2S3 nanorods are due to the presence of NaOH which controls the nucleation and growth process of Bi2S3 nanorods. The photocatalytic activity of the Bi2S3 nanocrystallites has been estimated by the degradation of methylene blue (MB) under the irradiation of halogen light. It was noted that the absorption peak corresponding to MB reduced indicating the photocatalytic nature of the sample. In these conditions, the maximum degradation of the dye was achieved within 140 min for KOH added Bi2S3 samples and the photodegradation efficiency is 87.98%. A possible photocatalytic reaction mechanism of the Bi2S3 samples has also been proposed.

Hexagonal phase zinc oxide (ZnO) nanostructures were synthesized via hydrothermal method and annealed at different temperatures viz., 200, 400, 600, 800 and 1000 °C. The prepared nanostructures were characterized by XRD, FTIR, FESEM, HR-TEM, UV-DRS and XPS techniques. The crystallite sizes of the prepared nanomaterails were calculated by Williamson–Hall plots method. The ZnO annealed at 200 °C showed a crystallite size of 18.7 nm while the ZnO annealed at °C showed a 46.2 nm. It is observed that when increasing the annealing temperature the crystallite sizes were increased due to induced growth of crystallites during annealing process. Moreover, the band gaps of the ZnO annealed at different temperatures showed a decreasing trend with increasing annealing temperatures. The photocatalytic performances were studied by analyzing the degradation of methylene blue in an aqueous solution. ZnO annealed at 1000 °C exhibited better photocatalytic activity (94%) due to enhanced crystallinity, comparatively lower bandgap and high oxygen vacancy.

MXene is a growing class of two-dimensional layered material that has been showed promising application in various energy storage and conversion technologies, due to its unique electrical, mechanical, surface and electrocatalytic properties. One of the promising applications of MXene is, its definite role as durable catalyst support material, for fuel cell anodic/cathodic reactions. Very recently, MXene supported catalysts have been identified as potential and stable support for various Pt and non-Pt metals designed for cathodic oxygen reduction reaction and it has been proved as excellent material to enhance the oxygen reduction kinetics. This had motivated the researchers to explore MXene as catalyst support for anodic methanol/ethanol oxidation reactions. In this review, recent developments in experimental and theoretical research on MXene-based electrocatalysts for the methanol/ethanol oxidation reactions are examined and overviewed. After careful examination of the available literature, we presume that MXene supported electrocatalyst showed enhanced methanol/ethanol oxidation kinetics and therefore believed to have tremendous opportunities as durable catalyst support for alcohol fuel cells. However, researchers also consider several limitations and challenges that must be addressed for efficient application of MXenes as catalyst supports. Therefore, current research on MXenes with respect to the methanol/ethanol oxidation are discussed, with a focus on synthesis strategies, oxidation kinetics, and factors responsible for enhancing the electrocatalytic performance. Several strategies for the further development of efficient and durable MXene supported catalysts are also proposed.

To produce xylo-oligosaccharides (XOS) from the agriculture waste, which included, green coconut and vegetable cocktail. The two pretreatment - hydrogen peroxide-acetic acid (HP-AC) and sodium hypochlorite-sodium hydroxide (SH-SH) - were used for this study. The optimal conditions for the pretreatment were 80°C, 4.0% NaClO, and 2 hours, followed by 0.08% NaOH, 55°C, and 1 hour. Further enzymatic hydrolysis of green coconut (GC) and vegetable cocktail (VC) were performed and found in case of GC, the best outcomes were observed. Different types of XOS were obtained from the treated biomass whereas a single type of XOS xylo-pentose was obtained in high quantity (96.44% and 93.09% from CG and VC respectively) with the production of other XOS2%. This study presents a reasonably secure and economical method for turning secondary crop residue into XOS and fermentable sugars.

In this study, we examined the highly selective sensing of Fe3+ ions in water using metal complex-functionalized mesoporous silica materials. Metal complex-functionalized mesoporous silica materials were synthesized on the mesoporous surface of SBA-15 via complexation process between Eu3+ and aminosilane groups. Mesoporous silica, SBA-15, and the Eu3+-complex functionalized SBA-15 were characterized using X-ray diffraction (XRD), transmittance electron microscopy (TEM), nitrogen sorption behavior, and Fourier transform infrared (FTIR) spectroscopy. The sensing behavior of the Eu3+-complex functionalized SBA-15 was studied using various metal ions (Fe3+, Cu2+, Cr3+, Co2+, Hg2+, Pb2+, and Zn2+) aqueous solutions. Photoluminescence intensity (λ = 612 nm) of the Eu3+-complex functionalized SBA-15 was dependent on the different interactions between metal ions and Eu3+-complexes. Photoluminescence intensity at λ = 612 nm of the Eu3+-complex functionalized SBA-15 decreased to near zero and proved the highly selective sensing effect of Fe3+. Therefore, the Eu3+-complex functionalized SBA-15 can be considered an excellent candidate for sensing iron ions in water.

Photocatalysis is one of the fascinating fields for the wastewater treatment. In this regard, the present study deals with an effective visible light active BiYO3/g-C3N4 heterojunction nanocomposite photocatalyst with various ratio of BiYO3 and g-C3N4 (1:3, 1:1 and 3:1), synthesised by wet chemical approach. The as-synthesised nanocomposite photocatalysts were investigated via different physicochemical approaches like Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electrons microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical studies to characterise the crystal structure, morphology, optical absorption characteristics and photoelectrochemical properties. The photocatalytic degradation ability of the prepared photocatalytic samples were also analysed through the degradation of RhB in the presence of visible light irradiation. Of all the synthesised photocatalysts, the optimised CB-1 composite showed a significant photocatalytic efficiency (88.7%), with excellent stability and recyclability after three cycles. O2.− and •OH radicals were found to act a major role in the RhB degradation using optimised CB-1 composite and it possessed ~ 1 times greater photocurrent intensity than the pristine g-C3N4 and BiYO3. In the present work, a direct Z-scheme heterojunction BiYO3/g-C3N4 with a considerably improved photocatalytic performance is reported.

A novel FeMoO4/g-C3N4-2D/2D Z-scheme heterojunction photocatalyst was prepared via wet chemical method. The observed structural morphology of FeMoO4/g-C3N4 reveals the 2D-iron molybdate (FeMoO4) nanoplates compiled with the 2D-graphitic carbon nitride (g-C3N4) nanosheets like structure. The photocatalytic activity of the g-C3N4, FeMoO4, and FeMoO4/g-C3N4 composites were studied via the degradation of Rhodamine B (RhB) as targeted textile dye under visible light irradiation (VLI). The optimal FeMoO4/g-C3N4 (1:3 ratio of g-C3N4 and FeMoO4) composite show an enhanced degradation performance with rate constant value of 0.02226 min-1 and good stability even after three cycles. Thus, the h+ and O2•－are the key radicals in the degradation of RhB under VLI. It is proposed that the FeMoO4/g-C3N4 Z-scheme heterojunction effectively enhances the transfer and separation ability of e-/h + pairs, by the way increasing the photocatalytic efficiency towards the RhB degradation. Thus, the newly constructed Z-scheme FeMoO4/g-C3N4 heterojunction photocatalyst is a promising material for the remediation of wastewater relevant to elimination of toxic effect in marine environment.

Excess sludge produced from biological wastewater treatment plant in petroleum industry is a kind of hazardous solid waste. Converting the sludge into biochar catalysts may help to reduce its environmental risk, recover resources and increase economic efficiency. However, the role of the sludge biochar in persulfate activation remains unclear, limiting its application in removing organic pollutants from water body. In this study, metal-rich petrochemical sludge was used to produce activated sludge biochar (ASC) via a two-step method of pyrolytic carbonization (400 °C-800 °C) and subsequent KOH activation (abbreviated as ASC 400-800). The physio-chemical properties of ASC 400-800 were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and Raman. The chloramphenicol (CAP) removal performances of ASC 400-800/peroxymonosulfate (PMS) systems were evaluated. Results showed that porous sludge biochar was successfully prepared by the two-step method. At 800 °C, the specific surface area of ASC reached the highest value of 202.92 m

The development of efficient, scalable, and economically viable electrode materials with high specific capacitance is of great significance for supercapacitor applications. Herein, α-Fe2O3 nanoparticles, α-Fe2O3/rGO, and α-Fe2O3/SnO2/rGO nanocomposite were synthesized by a one-step hydrothermal method. Different characterization techniques were used to study the physical and chemical properties of the prepared materials. The powder XRD measurement revealed that the formation of the ternary composite without any impurities. As characterized by SEM and TEM techniques, both α-Fe2O3 and SnO2 nanoparticles were embedded on two-dimensional reduced graphene oxide sheets. The electrochemical properties of the prepared electrode materials were studied by cyclic voltammetry and galvanostatic charge/discharge, and impedance spectroscopy techniques in a 6 M KOH electrolyte solution. All the electrode materials exhibit Faradic reaction peaks in CV curves which imply the pseudocapacitive nature of the prepared materials. The ternary α-Fe2O3/SnO2/rGO nanocomposite demonstrated the enhanced specific capacitance of 821 Fg−1 at 1Ag−1 than that of α-Fe2O3 nanoparticles (373 Fg−1 at 1Ag−1), and α-Fe2O3/rGO (517 Fg−1 at 1Ag−1) nanocomposite with excellent cyclic retention (98.7%) after successive 10,000 cycles. This improved electrochemical performance of ternary α-Fe2O3/SnO2/rGOnanocomposite is mainly attributed to the surface properties of nanostructures of metal oxides and an excellent conductive network. Moreover, the asymmetric supercapacitor (ASC) device was fabricated using the ternary α-Fe2O3/SnO2/rGOnanocomposite as the anode material and rGO as the cathode material. The ASC device showed an energy density of 17 Wh Kg−1 at a power density of 3585 W kg−1 and retains 94.52% capacitance after successive 5000 cycles at a current density of 10Ag−1.

A very ecofriendly heterogeneous catalytic method has been used for the highly selective synthesis of octahydroaminoacridine/1,2,3,4,5,6,7,8-octahydroacridin-9-amine (OA) by a single-step vapor pha...

A very green catalytic method has been introduced for the synthesis of alkylaromatic ketones by solvent-free benzylic oxidation of alkylaromatics with molecular oxygen (O2) over hexagonally mesostructured MnSBA-15 catalysts synthesized with a variety of manganese (Mn) contents using a pH-adjusting direct hydrothermal (pH-aDH) method. For example, the solvent-free oxidation of ethylbenzene (EB) over different mesoporous MnSBA-15 catalysts and uniform pore sized MnMCM-41(31) prepared by an alkaline hydrothermal method has been systematically evaluated. Washed MnSBA-15(4) (W-MnSBA-15(4)) or green mesoporous MnSBA-15(4) obtained after the removal of the non-framework octahedral Mn2O3 species deposited on the active surface of MnSBA-15(4) using a promising chemical treatment method is used for this reaction to evaluate its catalytic activity. Meanwhile the recyclability and hot-filtration experiments for this reaction have been also studied. The catalytic activities obtained from the above catalytic results prove that the W-MnSBA-15(4) has higher EB conversion and AP[double bond, length as m-dash]O selectivity than the other mesoporous catalysts used in this reaction. Therefore, in order to find the optimal reaction parameters for this reaction, various reaction parameters with W-MnSBA-15(4) have been thoroughly evaluated. Using W-MnSBA-15(4), the catalytic results obtained with different oxidants used in this reaction have also been discussed clearly. The catalytic results of solvent-free benzylic oxidations with W-MnSBA-15(4) conducted with different alkylaromatic molecules have been obviously discussed. All the mesoporous catalysts used in this reaction have been characterized using several instrumental techniques to confirm them as the standard mesoporous catalysts. The plausible reaction mechanism for the solvent-free oxidation of EB has been successfully reported based on the characterization results of the catalyst and catalytic results. The ESR and UV-vis DRS results of the W-MnSBA-15 catalyst used in these reactions corroborate that the disordered octahedral divalent (Mn2+) and tetrahedral trivalent (Mn3+)-species have been successfully incorporated on the silica surface of the catalysts. Based on the catalytic results, it is noteworthy to observe that mesoporous W-MnSBA-15(4) is a highly active, green and promising heterogeneous catalyst for the selective synthesis of alkylaromatic ketones, since the catalyst produces the best catalytic activity among the other mesoporous Mn silicate catalysts.